Granulator for granulating plastic strands

ABSTRACT

A support for the incoming plastics strands is disposed longitudinally of a knife cylinder. The support is in the form of a metal strip mounted in retaining means with one of its edges uppermost. The upper edge is adjustable in sections towards the knife cylinder, to compensate for wear.

Nov. 5, 1974 is in the form of a metal strip mounted in retaining means with pen- [56] References Cited UNITED STATES PATENTS 2,582,522 l/l952 Buttersby........,.,............... 3,196,724 7/l965 Frunk.......... 326L249 7/1966 Primary Examiner-J. M. Meister [57] ABSTRACT A support for the incoming plastics strands is disposed longitudinally of a knife cylinder. The support one of its edges uppermost. The upper edge is adjustable in sections towards the knife cylinder, to com sate for wear.

6 Claims, 1 Drawing Figure PLASTIQ STRANDS Inventor: Rudolf Paul Fritsch, Stuttgart,

Germany Assignee: Firma C. F. Scheer & Cie,

Baden-Wurttemberg, Germany Apr. 17, 1973 Foreign Application Priority Data Apr. 22, 1972 Germany............................ 2219784 83/3563, 83/699, 83/700, 83/856 Int. 823d 23/00, B29b 1/02 83/355, 356.3, 349, 700, 83/699, 612, 674, 356, 856-858 Unite States Patent Fritsch 41 GRANULATOR FOR GRANULATING 22 Filed:

21 Appl. No.: 351,865

[58] Field of Search GRANULATOR FOR GRANULATING PLASTIC STRANDS The invention relates to a granulator for granulating plastics strands, which has a knife cylinder and a support for the incoming strands disposed longitudinally of the knife cylinder.

The knife cylinder of such granulators do not wear uniformly over their length. Accordingly, there is a change of distance between the knife cylinder and that edge of the support which is nearest to the knife cylinder; however, this distance is important for the quality of the manufactured granulate and in the normal case must not exceed 0.01 mm. In known granulators with a rigid knife beam as support for the plastics strands it is therefore not possible to produce a uniform and highquality granulate after the knife cylinder has been in use for some time.

It is therefore an object of the invention to provide a construction which can take account of the irregular wear of the knife cylinder.

Accordingly, the present invention provides a granulator for granulating plastics strands, comprising a knife cylinder; a support for incoming plastics strands disposed longitudinally of the cylinder, the support being in the form of a metal strip one edge of which is uppermost and retaining means for adjustably holding the strip so that its upper edge is adjustable in sections towards the knife cylinder.

The upright or nearly upright metal strip being resilient, may be readily deformed towards the knife cylinder in individual sections, so that the distance between its upper edge and the knife cylinder may thus be exactly adjusted over the entire length of the knife cylinder.

A particularly simple construction for the retaining means (in which the strip may nevertheless be effectively adjusted towards the knife cylinder) comprises at least two parts, the two parts forming a clamping device for the strip, which is accommodated in a slit defined by this clamping device, the upper part of the slit being open towards the knife cylinder to enable the metal strip to be adjusted. Accordingly, the undeformed zones of the metal strip bear practically as far as the upper edge on the outer part, which faces away from the knife cylinder. The outer part may also be provided with a support surface for the incoming strands.

The construction of the adjusting facility of the metal strip is particularly inexpensive if the outer part of the clamping device, which faces away from the knife cylinder, is simply provided with adjusting screws disposed alongside the metal strip and positioned approximately perpendicularly thereto. By this simple means it is possible for the various sections of the metal strip to be effectively adjusted towards the knife cylinder almost independently of each other. it is advisable to provide locknuts for locating the adjusting screws.

It is also desirable to be able to adjust the support in the vertical direction. This can be easily achieved if screws with an eccentric are provided in the clamping device, below the metal strip for the vertical adjustment thereof. These screws may alternatively extend through apertures in the metal strip and need not necessarily be disposed below the metal strip.

The invention will be described further, by way of ex ample only, with reference to the accompanying drawing, which is an end view of part of a granulator, the

support for the incoming plastics strands being shown partially in section.

The drawing shows a machine frame 310 on which bearing units 14 are mounted on both ends of a knife cylinder 12. The knife cylinder is covered by a hood 16 which exposes the knife cylinder above an anvil l8 and also forms a discharge (not shown) for the granulate.

A row of plastics strands 20 supported by the anvil 18 are delivered in the direction of the arrow A by feed means (not shown) and are then granulated by the knife cylinder 12. The anvil 18 consists substantially of three parts, namely a main clamping member 22 and an inner clamping member or jaw 24, which together define a slit 26, and an anvil knife 28, disposed in the slit 26 and taking the fonn of a hardened sheet metal strip. The anvil knife 28 is clamped by means of clamping screws 30 which extend through the main member 22 and tighten the clamping jaw 24 against the main member.

Eccentric screws 32 as well as adjusting screws 34 also extend through the main member 22. A row of such screws which are serially disposed alongside the anvil knife 28 are of course provided in each case, that is to say extending perpendicularly to the plane of the drawing. The eccentric screws 32 are each provided with an eccentric 32a which bears against the lower edge of the anvil knife 28. Adjusting of the eccentric screws therefore permits vertical. adjustment of the anvil knife. The outer face of the anvil knife is acted on by the row of adjusting screws 34 so that rotation of them causes the upper edge of the knife 28 to be advanced towards the knife cylinder 12. Lock nuts 34a are also provided for the adjusting screws 34.

It is convenient if the upper edge of the anvil knife 28 is approximately flush with a support surface 22a formed on the main member 22. Where appropriate, it is also possible to provide lock nuts for the eccentric screws 32.

To adjust the distance between the anvil knife and the knife cylinder it is merely necessary to rotate the adjusting screws 34 when the anvil knife is clamped between the clamping jaw 24 and the main member 22, the resilience of the anvil knife permitting separate adjustment of different anvil knife zones.

1 claim:

1. A granulator for granulating plastic strands comprising a knife cylinder having a plurality of axially extending closely spaced knife edges disposed around the periphery of the cylinder and generally saw-toothed in radial section, a support for a plurality of incoming plastic strands to be granulated, said support including a flexible metal strip and a retaining means for adjustably holding said metal strip disposed in a plane generally tangential to an arc defined by said knife edges and with the upper edge of the metal strip disposed in coacting relationship with successive knife edges to successively shear the ends of the incoming plastic strands, said retaining means including means for deforming individual sections of the upper portion of the metal strip in a direction radially of the knife cylinder to compensate for longitudinally uneven wear of the knife edges.

2. A granulator as claimed in claim 1, in which the retaining means comprises a clamp having an outer clamping member supporting the surface of the metal strip facing away from the knife cylinder and having an inner clamping member which engages only along the der.

5. A granulator as claimed in claim 2, further comprising screws mounted on the clamp at right angles to the metal strip and each screw having an eccentric arranged for engagement with the strip for the vertical adjustment thereof.

6. A granulator as claimed in claim 5, in which each eccentric is arranged for engagement with the lower edge of the strip.

l l #k 

1. A granulator for granulating plastic strands comprising a knife cylinder having a plurality of axially extending closely spaced knife edges disposed around the periphery of the cylinder and generally saw-toothed in radial section, a support for a plurality of incoming plastic strands to be granulated, said support including a flexible metal strip and a retaining means for adjustably holding said metal strip disposed in a plane generally tangential to an arc defined by said knife edges and with the upper edge of the metal strip disposed in coacting relationship with successive knife edges to successively shear the ends of the incoming plastic strands, said retaining means including means for deforming individual sections of the upper portion of the metal strip in a direction radially of the knife cylinder to compensate for longitudinally uneven wear of the knife edges.
 2. A granulator as claimed in claim 1, in which the retaining means comprises a clamp having an outer clamping member supporting the surface of the metal strip facing away from the knife cylinder and having an inner clamping member which engages only along the lower part of the face of the metal strip facing towards the knife cylinder, to permit adjustment of the upper edge of the metal strip.
 3. A granulator as claimed in claim 2, in which the outer clamping member is formed with a support surface for the incoming strands.
 4. A granulator as claimed in claim 2, further comprising adjusting screws in the outer clamping member, the ends of the screws being arranged to abut against the face of the strip facing awaY from the knife cylinder.
 5. A granulator as claimed in claim 2, further comprising screws mounted on the clamp at right angles to the metal strip and each screw having an eccentric arranged for engagement with the strip for the vertical adjustment thereof.
 6. A granulator as claimed in claim 5, in which each eccentric is arranged for engagement with the lower edge of the strip. 